Tandem, Visible Light and RF Communication System

ABSTRACT

A system having first and second different communication system can include a plurality of illumination devices having modulatable optical output signals. A plurality of building control units are in wireless communications with one another. Representative units could include ambient condition detectors, intrusion detectors, output devices or actuators. At least some of the units include optical sensors responsive to the modulatable optical output signals, and, wherein in responsive to received, modulated optical output signals, the respective control unit carries out a predetermined function.

FIELD

The application pertains to multi-modal communications systems. More particularly, the application pertains to such systems which incorporate multiple, wireless communications systems of substantially different wavelengths which can operate in tandem.

BACKGROUND

Various types of wireless RF communications systems are known for use in building automation, monitoring and control systems. While useful, there are limitations as to the type of functionality that such systems can provide. Such systems can also suffer from eavesdropping and exposure to foreign third parties along with power related limitations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a system in accordance herewith.

FIG. 2 is a block diagram of an illumination element in accordance herewith; and

FIG. 3 is a block diagram of a radio frequency enabled device in accordance herewith.

DETAILED DESCRIPTION

While disclosed embodiments can take many different forms, specific embodiments hereof are shown in the drawings and will be described herein in detail with the understanding that the present disclosure is to be considered as an exemplification of the principles hereof, as well as the best mode of practicing same, and is not intended to limit the claims hereof to the specific embodiment illustrated.

Visible Light Communication (VLC) is a non-disruptive wireless communications solution made possible by the advent of light emitting diode (LED) building illumination systems. A key property of LED lighting is that it can be amplitude modulated at very high rates, providing good data transmission without affecting the illumination function itself.

VLC has several advantages over traditional RF communication systems; the operation is unlicensed, the transmission path is contained (by walls), so spatial re-use is not an issue, nor is eavesdropping beyond the room/building walls a problem. Further the cost of transmission and reception is low. Since wavelengths are short, there are good ranging and location opportunities. The downsides of VLC are short operating range and of course the lights need to be powered and modulated to operate as a communications service in addition to providing illumination.

In fact RF communications and VL communications operating together offer several complementary properties. As discussed below, complementary or tandem operation offers additional control configurations not available with a single wireless system.

Examples of functionality available with multi-modal communications systems follow. The particular characteristics of the different types of communications systems can be selected and allocated to implement various functions which might be difficult or expensive to implement with one type of communications system but which can be very cost effectively provided with the second type of system.

Those of skill will understand that the following are exemplary only and are not limitations hereof. Numerous additional possibilities are available with multiple complimentary communications systems.

In particular the following exemplary functionality is possible with VLC and RF communication systems operating in tandem. The following examples contribute to extending battery life of wireless units. Synchronized sirens, or sounders, can be provided for battery-powered smoke detectors. In such instances, if one goes, all go sound operation is possible. Redundant operation preserves batteries in the RF emergency devices by using VLC communications when the lights are on, and RF when they are not.

Synchronizing optical signals can be sent to RF transceivers at much lower operating current in the battery powered device than would be possible if synchronization was via the RF signals. In-building location services can be provided. In this regard, a security system portable tablet control unit, or phone could use its built-in camera to detect the nearest modulated LED light fixture, and therefore its location, again enabling smart room operation.

In yet another aspect, smart room RF based functionality can be augmented. For example, a manually operated light switch can indicate occupancy and can trigger other devices in the illuminated area when the light is turned on or energized. A shade or blind can automatically be closed when the light is turned on. Similarly, the heat could be turned on, or up or a door locked, or unlocked in response to a light being turned on. Status requests to remote detectors could reduce overall quiescent current if the request to the battery powered detector was via VLC with the sensor response via RF. Those of skill will understand that these are examples, and not limitations hereof.

In principle, the enabling technology includes an ability to amplitude modulate individual LED light fixtures in conjunction with the capability of high speed photo diodes to detect messages in building control products and portable devices. As those of skill will understand, the examples disclosed here require various data protocols—both RF and visible light to enable timing accuracy for timing and synchronization. Addressable lighting fixtures and control devices that can detect RF and/or VLC signals are useful in the present context.

Further, elements of the VLC system can transmit a change of status indication, for example, “turning-off”, to alert local RF devices. Alternately, a change of status message indicating “light on” could also be transmitted.

FIG. 1 illustrates a system 10, in accordance herewith installed in a building B. Building B has two floors indicted by spaces S1, S2. A plurality 12 of detectors and/or output devices 12 a, 12 b, 12 c . . . 12 n which can be in wireless RF communication R are illustrated scattered throughout the building B as would be understood by those of skill in the art.

The plurality 12 can include fire or gas detectors, intrusion or other security monitoring detectors, output devices such as audible or visual alarm indicating devices as well as solenoids or other types of actuators all without limitation. For example, unit 12 a can be implemented as a fire detector, 12 b, could be implemented as a gas detector and 12 c could be implemented as an intrusion detector. Unit 12 d can be an actuator which could implement a linear motion in response to a received command. All such devices can be in wireless RF communication R with a displaced monitoring system control unit 16.

Other devices in a plurality 18 can emit visible light and provide both an illumination function as well as modulated beams of radiant energy V which can provide a second communications mode which can compliment the above noted RF communications mode of operation. For example devices 18 a, 18 b, 18 c . . . 18 p can provide illumination to the respective adjacent regions such as S1-1, S1-2 . . . S1-n in space S1, or S2-1, S2-2 in space S2. In addition such devices can emit modulated beams of visible radiant energy V which can provide additional, or different control functions than provided by the wireless RF system.

For example, manually operable switch 20 can be used to turn on a light emitting diode source 18 b which can not only provide illumination in sub-region S2-1 but also emit the above noted modulated, visible, radiant energy V which can in turn cause actuator 12 d to open or close a curtain, or shade, C, or unlock a door. Radiant energy signals V from switch 20 could also provide synchronization signals to detectors, or output devices 12 b,c. The devices 12 b, c can then communicate via RF communication links R with the monitoring system 16 or other units in the building B.

FIG. 2 is a block diagram of an illumination element, such as 18 i in accordance herewith. Element 18 i includes a housing 40 which carries a source 42 of visible light. For example, one or more light-emitting-diodes. Control circuits 44 can energize the source 42 to provide both visible light for illumination and a modulated, coded, data sequence which can be detected and responded to by other units in the vicinity of element 18 i.

Optionally, unit 18 i can also include an RF transceiver 46 and one or more sensors 48 as desired. Those of skill will understand that exemplary illumination element 18 i can implement a variety of communications modes in accordance herewith to maximize battery life of the various wireless units 12 i or to provide additional “smart house” functionality as desired.

FIG. 3 is a block diagram of a detector or actuator 12 i such as 12 a-12 d. The unit 12 i can be carried by a housing 50 and include alight sensors 52 which can respond to coded messages from element 18 i as described above. Control circuits 54 can decode messages received from sensors 52, and/or RF messages received from transceiver 56. The units such as 12 i can carry one or more condition sensors and/or actuators as at 58 all without limitation. Units, such as 12 i can be energized by batteries B whose life can be extended by the above described processes of using multi-model communications.

From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims. 

1. A multi-mode communication system comprising: a plurality of devices; a radio frequency communications system which provides wireless communications between members of the plurality of devices; and a visible light communications system which provides different communications than provided by the radio frequency system between at least some of the devices of the plurality, and, wherein the two systems operate in tandem to implement selected functionality.
 2. A system as in claim 1 where the devices are selected from a class which includes at least manually operable light switches, ambient condition detectors, intrusion detectors, building control devices, regional access control equipment, actuation units and audio output devices.
 3. A system as in claim 1 wherein the visible light communications system includes visible light transmitters which can also illuminate regions in the vicinity of respective ones of the transmitters.
 4. A system as in claim 1 wherein at least some of the devices include at least one visual light sensor and at least one of a radio frequency receiver, or transmitter.
 5. A system as in claim 1 where at least one device includes at least one light emitting diode to provide local illumination and to provide modulated optical outputs.
 6. A system as in claim 2 wherein at least some of the devices include at least one visual light sensor and at least one of a radio frequency receiver, or transmitter, and, which includes at least one light emitting diode to provide local illumination and to provide modulated optical outputs.
 7. A system as in claim 2 where the visible light communication system provides synchronization signals to at least some of the devices.
 8. A system as in claim 7 where in the event that the visible light communication system is not available, the radio frequency communications system provides at least some synchronizing signals.
 9. A system as in claim 7 where at least some of the devices include light emitting diodes which are modulated to generate visible beams of control signals as well as providing local illumination.
 10. A system comprising: a plurality of illumination devices having modulatable visible output signals; a plurality of building control units which are in wireless communications with one another, and wherein at least some of the units include optical sensors responsive to the modulatable visible output signals, and, wherein in responsive to received, modulated, visible, output signals, the respective control unit carries out a predetermined function.
 11. A system as in claim 10 wherein in the absence of the visible output signals at least some of the control units communicate via radio frequency signals.
 12. A system as in claim 11 where the control units are selected from a class which includes at least manually operable light switches, ambient condition detectors, intrusion detectors, building control equipment, regional access control equipment, actuation units and audio output devices.
 13. A system as in claim 11 wherein the illumination devices emit a change of state message when illumination is being terminated.
 14. A system as in claim 13 wherein a second change of state message is emitted when illumination is being enabled.
 15. A system having first and second different, wireless, communication systems comprising a plurality of illumination devices having modulatable optical output signals, a plurality of building control units in wireless communications with one another, via non-optical signals, wherein representative units are selected from a class which includes at least ambient condition detectors, intrusion detectors, output devices or actuators wherein at least some of the units include optical sensors responsive to the modulatable optical output signals, and, wherein in responsive to received, modulated optical output signals, the respective control unit carries out a predetermined function and communicates non-optically in connection therewith.
 16. A system as in claim 15 where in the absence of modulated optical signals, the units communicate via non-optical signals.
 17. A system as in claim 16 wherein the illumination devices also provide local illumination.
 18. A system as in claim 17 where the non-optical signals comprise radio frequency signals.
 19. A system as in claim where the optical output signals provide synchronization signals.
 20. A system as in claim 19 where in the absence of optical output signals, at least some synchronization signals are provided via radio frequency signals. 